Fusible link



J. D. ALEXANDER Jan. 27, 1925.

FUSIBLE LINK Filed March 8, 1923 Patented Jan. 27, 1925.

onrrn JOHN D. ALEXANDER, or PHILADELPHIA, J?ENNSYLVANIA.

FUSIBLE LINK. 4

Application filed March 8, 1923. Serial No. 623,784.

To all whom it may concern:

. Be it known that I, JOHN D. ALEXANDER, a citizen of Hungary (who has declared his intention of becoming a citizen of, the United States), residing in Philadelphia, Pennsylvania, have invented a Fusible Link, of which the following is a specification.

One object of this invention is to provide a novel form of temperature responsive link which in all of its various embodiments, shall be characterized by simplicity of construction, certainty of action under predetermined temperature conditions and by the tendency of its elements to laterally separate when the alloy normally connecting them is fused.

These objects and other advantageous ends I attain as hereinafter set forth, reference'being had to the accompanying drawings, in which,

Fig. 1 is a side elevation of a sprinkler head showing in vertical section oneform of my fusible link;

Fig. 2 is a front elevation of the fusible link shown in Fig. 1;

Figs. 3 and 4: are perspective views of two of the component parts of the links shown in Figs. 1 and 2;

Fig, 5 is a front elevation of a modified form of fusible link embodying my invention- Fig. 6 is a vertical section on the line 66, Fig. 5;

Figs. 7 and 8 are perspective views of the two main parts of the link shown in Figs. 5 and 6;

Fig. 9 is an elevation of the key member forming part of the linkshown in Fig. 5;

Fig. 10 is a front elevation of another modification of my invention; I

Fig. 11 is a vertical section on the line 1111, Fig. 10; and,

Figs. 12, 13, 14, are perspective views illustrating the construction of the elements vof the link shown in Fig. 10.

In Figs. 1 to 4 of the above drawings, 1 represents the threaded nozzle or base structure of a sprinkler head which includes also a yoke 2 carrying a central threaded spindle 3 supporting a water spreader which is axially in line with the passage through the base 1. The outlet of this passage is normally closed by a valve 5, between which and the spindle are mounted a pair of coacting levers 6 and 7 having projecting arms held together by the temperature responsive link constituting one form of my invention. As illustrated in Figs. 1 to'4c inclusive said link consists of twosimilar plates 8 and 9 each having an opening 10 for the reception of the projecting arms of the levers 6 and 7. Each of these plates is provided with two oppositely extending projections 11---11 in. the form of pressed out or struck-up tongues or portions of substantially semi-conical configuration. These two struck-up portions not only extend from opposite faces of each plate but are preferably on opposite sides of the center line of the link which passes through the opening 10. i s

In addition tothe plates 8 and 9, I provide two other similar plates 12 and 13 (Fig. 4) which are substantially rectangular in outline and are preferably each notched at. top and bottom so that they do not close the openings 10 in the plates 8 and 9. Each of the plates 12 and 13 has a pair of oppositely projecting tongues or pressed out portions 15 and 16, similar to those of the plates 8 and 9 and like them spaced at equal distances on opposite sides of the center line passing through the recess or notches 17..

For example, the plates 8 and 9 of the link lie in the same plane, with the two plates 12 and 13 in engagement with their opposite faces, the projections 11'1l of said plates. 8 and 9 extending into depressions formed by pressing out the projections 15 and 16 respectively of the plates 12 and 13. The four plates when properly assembled as shown are sweated orsoldered together by fusible alloy or other suitable material melting at a relatively low and predetermined temperature, so that under normal conditions a linkhaving' the 'construction shown in Fig. 2, will connectand hold together the arms of the levers 6 and 7, thus preventing opening of thevalve 5 of the sprinkler head. When however, the temperature in the vicinity of the link rises above the predetermined point, as for example above 165 F., the fusible material connecting the plates melts and owing to the tension applied to the link through the levers, the plates move laterally apart by reason of the coaction of the inclined projections 11 and 15, 11 and 16. There is thus no possibility of the plates failing to move far enough to permit the levers6. and 7 separating and the subsequent opening of the valve 5, nor is there any possibility of said plates being held together after they have began to separate by reason of the solidification of the fusible alloy due to its sudden cooling.

In that form'of my invention shown in Figs. 6 to 9 inclusive, I provide a link comprising two main plates 18 and 19 which may be either identical in construction -or slightly different as regards the depth of the pocket formed therein. This pocket is provided by pressing; or stampingout of the plate a'substantially rectangular tongue 20 so'that it lies parallel with thebody of the plate .and forms a ledge or abutment immediately adjacent the opening left or formed by its displacement. In addition, each .of the plates is provided with an opening 21 for the reception of an arm of a lever such as those shown in Fig. 1, and the straight edge of each plate distant from this opening, is recessed at '22 to permit free pas sage of the lever arm when .the plates are assembled as shown .in Fig. 6.

For holding the plates together and insuring their relative lateral movement when the fusible metal connecting .them melts, I provide a key member 28 which consists of a flat piece of sheet material including two partslying at. an obtuse angle to each other. The dimensions .and constrnct-ionof this key member are such that when the plates 18 and 19 are placed parallel so that their tongues20 project in opposite directions, the said member-23 may be mounted with one part in one of the .pockets between the tongues thereof and the adjacent fiat face of the other plate. The second part of said key member projects at an angle to the planes of the plates into the pocket of the second plate as shown in Fig. .6, so that the opposite ends of said member abut upon the bottomsof the two pockets. The three elements of the link are then soldered or sweat-- ed together wit-lithe relatively fusible alloy and as before when exposed to an abnon mall-y high temperature, the key member 23 will act to force the plates 18qand 19 laterally apart, uponmelting of the fusible metal.

The link illustrated in Figs. 10 to 15 in elusive consists of two-plates 2525 offsimilar construction each having an opening 10 for the reception of a lever arm or other part to be connected with the link and each likewise having portions of its straight edge distant from the opening 10 bent in opposite directions substantially at right angles to its plane as indicated at 26. Each of these lips 26 preferably has a width substantially half that of the plateand is designed to receive-one end of a strut in the form of a fiat or slightly bent plate 27likewise one half the width of the plate 25. There are thus two struts for each ofv the plates .25, lying immediately adjacent and substantially parallel with the latter, and

when the parts of the link are assembled, each strut of one of the plates 25 is connected to the corresponding strut of the plate 25 by a hooked tension member 28 in the form of a plate whose ends are turned over or given a hook form so as to engage the free ends or edges of the struts 27 in the manner shown in Fig. 11.

This eight part link, as in the other forms of my invention, has its various plates connected by relatively fusible metal or suitable alloy so that it will successfully resist tensible stresses for long periods of time without failure as long as the temperature remains below a predetermined point. When, however, the predetermined temperture is exceeded, the parts of the link coact to laterally force apart the tension members ,2'8 and the plates 25 and the struts 27 swing outwardly on the ledges or lips 26. As in the otherrforms of my invention, the arrangement described operates with certainty when subjected to a predetermined abnormal temperature and at the same time its construct-ion is such that it will not fail even though under tensionfor-long periods. Moreover, it will be .noted that the link is simple in construction,easily assembled and is relatively inexpensive.

I claim 1. A fusible link comprising .a pair of end members supported at certain points; each end member having a pair of oppositely extending projections spaced respectively on opposite sides of said points; a pair of intermediate members. having inclined portions adapted to cooperate with said firstmentioned projections so positioned as to tend to cause said intermediate plates to move laterally when a force is applied to said end members; and means for normally securing said members together under predetermined operating conditions.

2. A fusible link con'iprising, a pair of on d members having a pair of oppositely eX- tending projections, the projections on one member being oppositely disposed with respect to those upon the other member; a

pair of intermediate plates having complementary projections so. positioned as to cause said plates to separate when a forceis applied to said .end members; and temperature responsive means for normally securing said parts together.

The combination in. a fusible link of two end plates; each having two oppositely extending inclined portions; two iutm mediate plates each having two pairs of inclined portions positioned :to respectively coact with the inclinedportions of said end plates to cause lateral movement of said intermediate plates when the end plates move apart; and relatively fusible material normally connecting all of said plates.

4. In a fusible link, the combination with a pair of end plates, each plate having a the first-mentioned projections in such manpair of inclined projections extending ner that said intermediate plates tend to respectively from opposite sides thereof; of separate when a force is applied to said end a pair of intermediate plates positioned plates; and relatively fusible material nor- 5 respectively on opposite sides of said end Ina-11y connecting said plates together.

plates, each intermediate plate having oppositely inclined projections co-act-ing with JOHN D. ALEXANDER. 

